Electric Field Calculator
Calculate the magnitude of the electric field created by a point charge.
Electric Field Magnitude (E):
Understanding Electric Fields
An electric field is a region of space around an electrically charged particle or object in which an electric charge would feel a force. The electric field (E) is a vector quantity, meaning it has both magnitude and direction.
E = k · |q| / r²
Where:
- E is the electric field strength (N/C or V/m).
- k is Coulomb's constant (approx. 8.987 × 10⹠N·m²/C² in a vacuum).
- q is the magnitude of the source charge (Coulombs).
- r is the distance from the charge (meters).
Direction of the Field
By convention, electric field lines originate from positive charges and terminate on negative charges. This means:
- For a positive source charge, the field points away from the charge.
- For a negative source charge, the field points towards the charge.
Effect of the Medium
The standard formula assumes the charge is in a vacuum. If the charge is inside a material (like water or oil), the electric field is reduced by the material's dielectric constant (or relative permittivity, εr).
E_medium = E_vacuum / εr
For example, water has a dielectric constant of about 80, meaning it weakens the electric field by a factor of 80 compared to air. This is why salt (ionic bonds) dissolves so easily in water—the electrostatic attraction between ions is drastically reduced.